From the Steam Store page:
The Save the World Edition includes Lacuna and the game’s atmospheric soundtrack that lets you dive deep into the sci-fi noir world of Lacuna. In addition, Assemble Entertainment donates 10% of the revenues of this edition to Go Give One; a WHO initiative that provides COVID-19 vaccines amongst others for everyone, everywhere – prioritizing those who need them the most in countries that cannot afford them. On top of this, it’s the best option for all those who would like to support the work of the developer of Lacuna even more and do something good at the same time.